1. Field of the Invention
The present invention relates to the field of transluminal catheter procedures and interventions. In particular, the present invention provides a device and method for facilitating the rapid exchange of various therapeutic and diagnostic devices into the coronary arteries.
Percutaneous transluminal treatment of coronary artery disease frequently requires performance of multiple diagnostic and/or interventional procedures, each of which requires introduction of a different catheter. For example, intravascular ultrasound is often performed first and requires introducing a catheter having an imaging transducer into the heart. Following diagnosis, various therapeutic devices can be introduced into the heart, such as balloon angioplasty catheters, atherectomy catheters, laser ablation catheters, drug delivery catheters, and the like.
Before most therapeutic and diagnostic devices are introduced into a patient's vascular anatomy, a guiding catheter is first introduced into the heart as described generally in U.S. Pat. No. 5,163,921, the disclosure of which is herein incorporated by reference. The guiding catheter is typically inserted into the femoral artery in the groin and advanced towards the heart. The guiding catheter is directed through the patient's aorta until the distal tip of the guiding catheter reaches the ostium of one of the coronary arteries. Once the guiding catheter is placed in the ostium, various therapeutic or diagnostic devices can be inserted through the guiding catheter and into the coronary artery.
In order to introduce these devices beyond the distal end of the guiding catheter, a guide wire is commonly introduced through the guiding catheter. The distal end of the guide wire is advanced past the distal end of the guiding catheter and into the coronary artery. With the guide wire in place, a diagnostic or therapeutic catheter can be advanced over the guide wire and into the area of interest. The diagnostic or therapeutic catheter includes a lumen for receiving the guide wire, and the catheter is advanced over the guide wire in a manner often referred to as "tracking".
Frequently, it is necessary to exchange one therapeutic or diagnostic catheter for another. For instance, after initial diagnosis, it is usually necessary to remove the diagnostic catheter and replace it with an interventional catheter. Moreover, catheters having different sized balloons are often exchanged in an angioplasty procedure where lesions of the same vessel often require treatment with different size balloons. Following initial intervention, it is often desirable to reintroduce the diagnostic catheter to assess the progress that has been made. At the end of the treatment, it may be desirable to introduce a drug delivery catheter to perfuse the lesion with agents to inhibit restenosis. The exchange of catheters along a guide wire are described in U.S. Pat. Nos. 4,748,982; 4,762,129; 4,824,435; 4,850,358; and 5,024,234, the disclosures of which are hereby herein incorporated by reference.
In a particular procedure for exchanging catheters, the guide wire is left in place to protect the artery during the exchange. The guide wire is left in the artery because of complications that can arise when removing the guide wire, e.g., when the distal tip of the guide wire lifts a lesion flap, when the vessel spasms or abruptly closes making wire advancement impossible, or when placement of the guide wire simply takes too much time. To avoid these complications, the wire in this procedure is typically maintained in the vessel while the catheter exchange takes place.
Two techniques are generally employed for exchanging catheters when the guide wire is maintained in the artery. The first technique is used with catheters in which the guide wire lumen extends the full length of the catheter shaft. These are often referred to as "over-the-wire" catheters. When the "over-the-wire" catheter is withdrawn from the patient, guide wire position is maintained by holding the guide wire at its proximal end. To maintain a grip on the guide wire until the entire catheter is withdrawn from the patient, the guide wire must be long enough so that the proximal end of the guide wire can be held in place until the distal end of the catheter exits the patient. After the distal end of the catheter has been withdrawn from the patient, the grip at the proximal end of the guide wire may be withdrawn and the guide wire can be firmly held distal to the distal end of the catheter. The catheter can then be completely removed from the patient. The same procedure is performed in reverse to insert a different catheter into the patient.
In order to simplify catheter exchange, the second technique was developed which uses a "rapid exchange" catheter design. In the "rapid exchange" catheter, the guide wire lumen does not extend the full length of the catheter shaft. Instead, the guide wire exits the catheter shaft at some point near the distal end of the catheter. The remaining length of the guide wire runs alongside the catheter shaft until both the catheter and the guide wire exit the patient. This reduces the necessary length of the guide wire in comparison to the length required by the "over-the-wire" catheters.
One problem with existing intravascular systems arises from the need to position therapeutic or diagnostic devices into the narrow arteries of the heart The need to place the device over a guide wire requires that the distal end of the device be enlarged to accommodate the wire. The enlarged distal end can prevent the device from entering smaller arteries within the coronary vasculature. To overcome this problem, "common lumen" catheters have been developed as described in U.S. Pat. No. 5,203,338, the disclosure of which is hereby incorporated herein by reference. Common lumen catheters have a distal end having a single or common lumen and a proximal portion having at least two lumens, where one of the proximal lumens serves as a guide wire lumen. The common lumen catheter is inserted over a guide wire which has previously been inserted into the patient. After the common lumen catheter has been positioned at the desired location in the artery, the guide wire can be retracted from the distal region of the common lumen catheter and into one of the proximal lumens. This leaves the common lumen positioned in the distal region and available to receive the therapeutic or diagnostic device.
Despite improvements rendered by these techniques, certain difficulties still remain in performing coronary artery procedures. For instance, common lumen catheters occupy a substantial volume of the guiding catheter making it difficult to introduce contrast media through the guiding catheter. Additionally, even though the proximal portion of the common lumen is relatively large, space for housing the therapeutic or diagnostic devices is still limited. Because fewer devices can be stored in the common lumen catheter, the process of catheter exchange is slowed.
For these reasons it would be desirable to provide improved catheters and methods which overcome or reduce these and other problems.
2. Description of Background Art
Guiding catheters are described in U.S. Pat. Nos. 5,163,921 and 4,817,613.
As previously described, "rapid exchange" type catheters are described in U.S. Pat. Nos. 4,748,982; 4,762,129; 4,824,435; 4,850,358; 5,024,234.
As previously described, "common lumen" catheters are described in U.S. Pat. No. 5,203,338.
Other catheters employing guide wires are described in U.S. Pat. Nos. 5,201,316; 5,087,247; and 4,932,413, the disclosures of which are hereby herein incorporated by reference.